Effects of glycerin and glycerol monostearate on performance of thermoplastic starch

The effects of glycerin and glycerol monostearate (GMS) on a variety of pro perties of anhydrous wheat starch are explored by means of DSC, TGA, as wel l as mechanical, rheological and moisture sorption assessment. It is found that, as glycerin content (GC) increases, both melting point and degradatio n temperature decrease, and the range of the processing window extends. Mel t viscosity of the glycerin-plasticized starch depends on shear rate follow ing power law, exponentially on GC, and on temperature in Arrhenius type. I ncreasing GC leads to a linear increment of the equilibrium moisture sorpti on, which, however, can be depressed significantly by incorporating a small amount of GMS. Moreover, the presence of 2% GMS in the formulations can ef ficiently reduce the melt viscosity and enhance its temperature sensitivity while has insignificant effect on the non-Newtonian behaviour and mechanic al properties. (C) 2001 Kluwer Academic Publishers.